Demnite-time-limit relay



R. J. C. WOOD AND G. E. ARMSTRONG. DEFINITE TIME LIMIT RELAY. APPLICATION FILED MAR. 5. 191a.

PatenfedA'ug. 26,1919.

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APPLICATION HLED MAR. 5- 1918.

' Patented Aug. 26, 1919.

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REGINALD J. C. WOO D .AND GEORQE ARMSTBOIQ'Q, OF LQS ANGELES, CALIFORNIA.

DEFINITE-TIME-LIMIT RELAY.

Specification of Letters Patent. Patented Aug; 26, 1919 Application filed March 5, 19 18. eria1 No. 220,593.

To all whom it may concern:

Be it known that we, REGINALD J. C. Wool) and Gnonen ll ARMsrRoNe, both citizens of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented'a new and useful Definite-Time-Limit Belay, of which the following is a specification.

Our invention relates to the artof electric distribution, and the rincipal object of the invention is to provic e a definite "time limit relay which may be applied to a circuit breaker for the purpose of providing means for opening the circuit breaker a certain definite time after the appearance of any abnormal condition which the circuit breaker is designed to guard against.

A still further object of the inyention is to provide a definite time limit relay which will reset in. the event that the abnormal condition ceases before thecircnit breaker operates.

A still further object of the invention is to provied a definite time limit relay which will be wholly mechanical in its action and which will be readily adapted to be applied to certain existing types of circuit breaker without material modifications in said Cir cuit breaker.

A still further object of the invention is to provide a relay which can be adjusted to operate in a longer or shorter time and which can be readily changed to operate instantaneously if desired.

A still further object of the invention is to provide means by which the relay can be set to operate in a definite time in combination with means by which it can be instantly set to open instantaneously, the parts being so arranged that it can be then automatically and instantly returned to its original setting without any particular atten tion on the part of the operator.

Further objects and advantages will be made evident hereinafter.

Referring to the drawings, which are for illustrative purposes only,

Figure 1 is aside view of a particular type of the circuit breaker equipped with our invention.

Fig. 2 is an end view of the same circuit breaker with the operating handle broken off.

Fig. 3 is an end view of the circuit breaker with a ortion of the mechanism removed to better i lustrate the invention.

Fig. .4 is a Side view partly in Section of the relay with its hammer in its set position. v

Fig. 5 an end view of the relay.

In'the drawings a particular type of circuit breaker is illustrated. The invention, however, is applicable to practically all types'of circuit breakers as Will be readily understood by one skilled in the art.

The circuit breakers illustrated in the drawing consist of a base 11 en which is placed a pluralty of tanks 12, each of these tanks having a top 13 carrying porcelain bushings 14; through which the terminals 15 of the switch project. Operating bell cranks m l 1 d .1 Pin l8 rr ed in r m sf mounted on the tops 13, are prpvided. The bell cranks 17 are connected through bell crank connecting members 20, the end bell crank being provided with an operating extension 21 having a pin 22' to which a link mechanism is pivoted. This link mechanism consists of an upper link 25, anfintermediate link 26, and a lower link 27 The intermediate link 26 and; the lower link 27 are single and the npper link 25 is double, being provided with a projection 28 which is engaged by a pin 29 on the intermediate link 26, so that the parts, with the 'ci rcuit breaker closed, will assume the position shown in Fig. 1. A trip extension 30 is provided on the upper link 25. The lower link 27 is preferab y formed" integral with an operating bell crank 35 to which an operating handle 36 is attached. The operating bell crank 35 is rigidly secured to an operating bell'crank shaft supported in suitable bearings 38 attached to the base 11.

Mounted to slide freely up and down on a rod {l0 is a tripping weight il, this weight being normally held in its upper position, as shown, by means of a toggle, best shown in Fig; 3, composed of an upper link 42 and a lower link 43. A tripping rod 44 is pivoted on the connecting pin of the links .22 and 43 extending over and passing into the case of the definite time limit relay .45, which forms our invention.

Rigidly secured on the operating bell crank shaft 37 is a relay reset crank 46 to which a relay reset rod {17 is pivoted. Mounted ,on each of a series of insulators 50 is a trip coil 51, these trip coils being cone Inected through a conductor 52 with the cir- Qcuit to which the circuit breaker is connected and each being connected through a c d ts? w th o 9? the termina 15 f the switch. Each of the trip coils 51 is provided with a core 54 which is provided with an insulating trip coil rod 55. The trlp coil rods 55 each extend through an opening in a trip shaft lever 56 and are provided with a head 57. The trip shaft levers 56 are all connected rigidly to a trip shaft 60 carried and turning freely in bearings 61 mounted on the side of the switch. Rigidly secured on the trip shaft lever 60 is a lever carrying trip weight 62, which extends out and normally rests on a platen 63 of the definite time limit relay 45.

The above parts, with the exception of the relay reset lever 46, the relay reset rod 47 and the trip weight 62, are standard in the switch shown, the trip rod 44, however, in the standard form of switch being actuated directly from the trip shaft 60.

For the purpose of introducing a definite time limit in the tripping of the switch, we introduce the definite time limit relay 45. This relay consists of a main casting 101. Secured to the casting 101 is an operating casting 103 in which a relay shaft 104 is free to turn. Mounted on the outer end of the relay shaft 104 outside the case is a lever 105 to which the relay reset rod 47 is pivoted. The trip rod 44 extends through the casting 101, being supported in the position shown in Fig. 4.

Mounted in such a manner as to turn freely on the shaft 104 is a hammer 110, this hammer being so placed that it may be pulled around in a clockwise direction. as viewed in Fig. 4 into what is hereinafter called its set position, by means of a hammer spring 111 so that it strikes against the end of the trip rod 44. For the purpose of preventing it from so striking a latch 112 is provided, this latch being pivoted on a pin 113 carried in the casting 103 and being so formed that it catches in a notch 114 formed on the hammer 110.

Passing through the end of the latch 112 is a platen rod 115, this red carrying the platen 63 on its upper end. A plunger lever 116 is bifurcated, extending out on either side of the platen rod 115 and being connected to that rod by means of a pair of links 117. The plunger lever 116 is pivoted on a pin 118 secured in the casting 103 and has connected thereto a plunger lever spring 119.

Hung by a universal suspension on the bottom of the platen rod 115 is a dash pot 126, this dash pot fitting very closely over a plunger 1.27. A ball valve 128 closes a small opening 129 in the top of the dash pot 126 so that when the dash pot is pulled upwardly a partial vacuum is formed in the end thereof above the plunger 127, the ball valve 128 lifting, however, to allow the dash pot to pass downwardly with comparatively little resistance. The plunger 127 is held in its upper position by a spring 1301 and is rigidly connected to a plunger rod 130 which extends through the bottom of the casting 101 and is provided with a ring 131 into which the finger of the operator can be readily inserted.

Secured in the rod 130 is a calibration pin 132, this calibration pin extending through a slot 133 formed in a movable tube 134. The tube 134 is split and clamped by means of a screw 135 on a stationary inner tube 136, the stationary inner tube 136 having an inclined edge 137 against which the pin 132 ordinarily rests.

For the purpose of setting the hammer in the position as shown in Fig. 4 a reset arm 140 is rigidly secured on the relay shaft 104, this reset arm being preferably in the form of a pin which projects out and engages a reset pin 141 secured in the hammer 110. Secured to the shaft 104 is a spring arm to which a return spring 151 is secured. The springs 111, 119 and 151 are all tension springs secured through an ad justing means 152 at their lower ends to the casting 101.

The method of operation is as follows:

The circuit breaker is shown in its closed or operating position in Fig. 1. Whenever an abnormal current flows through any of the trip coils 51, the plunger 54 of that trip coil is pulled upwardly and the head 57 strikes on the under side of one of the trip shaft levers 56 pulling this lever upwardly and rotating the trip shaft 60 in a clockwise direction, as viewed in Fig. 2, thus lifting the trip weight 62 from the platen 63. The plunger lever spring 119, being relieved from the weight 62, then pulls the platen rod 115 upwardly thus pulling the dash pot 126 up vardly on the plunger 127. If the overload persists for the certain definite length of time for which the definite time limit relay 45 is set, the plunger lever 116 eventually strikes against the latch 112 throwing this latch out of engagement with the notch 114. We provide in the side of the dash pot 126 one or more small holes 200, these holes being so placed that they are uncovered while the plunger lever 116 is still a short distance below the point where it strikes against the latch 112, thus providing a quick hammer blow against the latch. As the dash pot 126 moves upwardly a partialvacuum is formed in the top thereof, this vacuum being gradually destroyed by the leakage of air around the plunger 127. It takes an appreciable time for this leakage to take place so that the plunger lever 116 moves upwardly slowly, the time required 1 for this movement depending upon the initial position of the plunger 127 with relation to the releasing ports 200. This is deter mined by the position of the pin 132 on the inclined edge 137 of the member 136, the

time being determined by the relative position ofthe sleeve 134 on the sleeve .136. The initial time setting for the breaker is therefore determined by suitable calibration marks on the sleeve 134, the relay being set by turning the sleeve 137 until the pin 132' is opposite the desired calibration marking. The vhigher the 7 initial position of the plunger 127 the longer the time necessary to trip the latch 112 after theoverload occurs.

In some cases it is desired to set the breaker for a certain time elementand yet arrange so that it can be tripped instantly if desired. This can be readily accomplished by pulling downwardly on the ring 131 and holding it in its lower position, thus pulling the plunger 127 down beldw' the openings 200 so that there is no appreciable retardation of the dash pot in its upward movement. finger ring 131 the original setting is restored so that no readjustment is necessary.

If for any reason the overload ceases before a suflicient time has elapsed to trip the latch 112, the weight 61 is dropped back on the platen 63, this weight being sufficient to force the dash pot downwardly against the spring 119, thus restoring the parts of the relay to their original condition.

As soon as the latch 112 is released the hammer 110, under the influence of the hammer spring 111 is thrown smartly around away from its set position, striking on the end of the trip rod 14 and forcing it to the right as shown in Figs. 2 and 3. This releases the toggle formed by the links 42 and 43 and the weight 41 drops striking on the extension 30 of the link 25. The weight ll thus breaks the toggle formed by the upper link 25 and the lower link 27, the breaking of this toggle allowing the circuit breaker to open under the influence of springs located inside the circuit breaker.

Whenever it is desired to recl'ose the circuit breaker the operating handle 36 is pulled outwardly and downwardly from the circuit breaker until the links 25 and 26 are again in approximately a straight line, the operating handle being then raised to close the breaker. When the operating handle 36 is forced downwardly, the weight 41 is reset through a trip weight reset rod 800. At the same time the relay reset rod 17 is forced upwardly forcing the relay reset lever to r0- tate in a counter-clockwise direction, thus rotating the relay shaft 104 in the same direction as viewed in Figs. 2 and 4. This rotation of the relay shaft 10 1 causes the reset arm 140 to force the reset pin 14:1 in the same direction, thus setting the hammer 110 by returning it to its initial or set position as shown in Fig. 1. When the handle 36 is forced upwardly in closing the breaker, the shaft 104 is rotated in a clockwise direc Intermediately upon releasing the tion thus returning the reset arm 1&0 to its initial position as shown in Fig. 4.

Since the opening of the circuit breaker will have relieved the overload, the weight 61 has already dropped on the platen 63, thus forcing the platen rod 115 downwardly so that the latch 112 is in a position to catch in the notch 111 and retain the hammer 110 in the position shown in Fig. 4:- The relay is therefore reset ready for a second operation. If an overload'exists when the circuit breaker is closed by lifting the handle 36, or if such an overload occurs for any reason at any time after the circuit breaker is closed, the cycle of operations just described is repeated.

It will be evident to one skilled in the art that while we have illustrated anddescribed our invention as applied to a particular type of circuit breaker, it nevertheless is applicable to many other forms. It will also be evident that while we have illustrated the circuit breaker as actuated by and used to protect the circuit from overloads, that by certain obvious modifications the definite time limit relay could be applied to a circuit breaker or made to operate under underload or over voltage or under voltage conditions. All such obvious modifications should be considered as falling within the scope of our invention, which should be limited only by the annexed claims.

What we claim is 1. In combination with a circuit breaker having arestraining means, a closing means, and a tripping means, a relay comprising a hammer s0 placed that it can strike and actuate said tripping means; a spring so formed and placed as to tend to cause said hammer to actuate said tripping means; a latch engaging and restraining said hammer in its set position; means for releasing said latch; and means by which said closing means resets said hammer.

2. A combination as'in claim 1 which also comprises a time limit means for delaying the operation of said means for releasing said latch.

3. A time limit device comprising a shaft; a hannner free to turn on said shaft; means for forcing said hammer into its set position; a hammer spring secured to said hammer in such a manner as to tend to turn said hammer on said shaft away from the set position of said hammer; a latch restraining said hammer in its set position; a plunger lever so placed as to trip said latch in its upper position; a latch spring tending to force said plunger lever from its lower position to its upper position; a weight sufficiently heavy-to hold said plunger lever in its lower position against the tension of said latch spring; means by which the occurrence of a predetermined condition removes the influence of said weight from. said plunger lever; and time element means for regulating the rate of travel of said plunger lever from its lower to its upper position.

i. A time limit device as in claim 3 in which the time element means comprises a dash pot having release ports in the side thereof, said dash pot being secured to said plunger lever; a stationary piston fitting inside said dash pot; and adjusting means for adjusting the initial position of said piston with relation to said ports and thus regulating the time element.

5. A time limit device as in claim l in which the adjusting means comprises a plunger rod spring tending to hold the piston in its upper position; and calibration means for fixing the distance said spring can move said plston upward.

6. A time limit device as in claim 5 in Which the calibration means comprises a plunger rod secured in said piston; a calibration pin secured in said plunger rod; and a member having an adjustable surface against which said plunger rod spring holds said calibration pin.

7. A time limit device as in claim 6 in which the member having the adjustable surface comprises a cylinder having a lower spiral face and in which is also provided a second cylinder having an axial slot in which said calibration pin slides.

In testimony whereof, We have hereunto set our hands at Los Angeles, California, this 27th day of February, 1918.

REGINALD J. C. WVOO'D. GEORGE E. ARMSTRONG.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). C. 

